It is often desired or necessary for medical reasons to deliver an implant into a bodily lumen, such as a lumen within the vascular, urogenital, and gastrointestinal systems. For example, stents may be delivered into any of these systems, embolic implants may delivered into blood vessels, and occlusion implants may be delivered into the fallopian tubes for sterilization purposes.
An example of an occlusive implant that is placed within the fallopian tubes for sterilization purposes is the Adiana® Permanent Contraception system (Hologic, Inc., Marlborough, Mass.). To use this system, a flexible delivery catheter is passed through the vagina and cervix and into each fallopian tube to deliver a low level of radiofrequency energy, followed by the delivery of a small, compressible occlusion implant. Implants are usually placed in the uterotubal junction, the narrowest part of the fallopian tubes. Such implants and procedures are described, for example, in U.S. Pat. No. 7,220,259, which is incorporated herein by reference.
Compressible implants, including occlusion implants, embolics, and stents, are often made from polymeric materials that allow for the compression of these implants into small profiles so that they may fit within the dimensions of their respective delivery devices. After the delivery device is positioned to a target location within the bodily lumen, the implant is extruded or otherwise released from the delivery device such that it self-expands from its reduced, delivery configuration into its intended expanded, working configuration. The expanded configuration may be necessary, for example, to apply forces against the surrounding bodily lumen wall to thereby keep the implant at the target location within the body.
Because many compressible implants are loaded into a delivery device at the point of manufacture rather than at the point of use, they are consequently kept in a reduced configuration within the confines of the delivery device during sterilization, shipping, and storage. During such time, the materials used in such compressible implants may undergo stress relaxation or other changes to mechanical properties that result from being held in a reduced configuration. If kept in the reduced configuration for too long and/or at elevated temperatures, the implant may not expand to a proper working configuration once released from its delivery device. The result is that many compressible implants have a short permissible shelf life and temperature exposure limitations.
It is an object of the present invention to provide for delivery devices and associated methods that allow for compressible implants to be sterilized, shipped, and stored for extended periods of time and/or at elevated temperatures without adversely affecting their properties or working function.